This invention relates generally to synchronizing arrangements and more particularly to synchronizing arrangements that include a torque lock feature.
U.S. Pat. No. 5,083,993 issued to Michael Oun Jan. 28, 1992 discloses a synchronizing arrangement for a planetary gear comprising a shift sleeve, two synchronization rings and two coupling rings that are more commonly referred to as blocker rings and clutch gears. The shift sleeve has internal coupling teeth at each end. When the shift sleeve is actuated, these internal coupling teeth cooperate with external teeth of the respective synchronization rings to synchronize the speeds of the shift sleeve and one or the other of the coupling rings. The internal coupling teeth of the shift sleeve then engage external teeth of the coupling ring at synchronous speed to lock the shift sleeve (and the ring gear attached to it) to the coupling ring.
The outer axial ends of the internal coupling teeth have tips that are shaped with sharp edges at the apex of chamfered or oblique surfaces. These tips confront tips of like shape at the axial ends of the external teeth of the synchronization rings and the coupling rings as best shown in FIG. 2 of the patent. The tips of the internal coupling teeth cooperate with the confronting tips of the synchronization rings and the coupling rings to guide the internal coupling teeth of the shift sleeve past the external teeth of the synchronization rings and into engagement with the coupling rings in a well known manner.
The two side walls or flanks of the internal coupling teeth of the shift sleeve and the external teeth of the coupling rings each have a back tapered surface adjacent each side of their respective tips that provide a torque lock feature that also operates in a well known manner to maintain engagement until the shift sleeve is purposely shifted out of engagement.
Synchronizing arrangements such as those disclosed in the Oun patent are often used in applications where at least one of the coupling rings is an integral part of or fastened to a helical gear which as a practical matter has some end play. Because of this end play, the helical gear is shifted axially in one direction or the other when torque is transferred to the helical gear by a mating helical gear. This torque responsive shift results in an over engagement of the torque lock surfaces when torque is transferred in one direction and an under engagement of the torque lock surfaces when the torque is reversed.